The field of the invention is that of high-power laser sources using an array of fibre lasers, capable of delivering a significant gain in extracted energy. Increasing the power, and in particular the energy, of fibre lasers constitutes a major challenge in many industrial, scientific (metrology, lidar, etc.) and optronic applications.
One of the limiting factors as regards the power generated as output by a fibre amplifier is the small core diameter of the fibre, whenever this is a single-mode fibre, and leads to the appearance of non-linear effects and/or a damage threshold in fibre amplifiers.
Two research approaches are currently being explored in laboratories, with the aim of paralleling a linear or matrix array of N or N2 fibre amplifiers by means of the following two techniques.
These are wavelengths multiplexing and coherent phase control of the fibre amplifiers, therefore constituting the equivalent of a phase array, using individual unit phase modulators coupled to each of the fibre amplifiers.
However, for a very large number of fibre amplifiers (typically greater than 100), the solution of wavelength recombination has limits, and especially in terms of spectral control.